A driver IC includes a first driver section for supplying driving signals to n output terminals and a second driver section for selectively switching one of m selection terminals (m≧3) to a predetermined potential. The first driver section includes a timing control circuit for generating timing signals that permit the second driver section to perform the selective switching. The timing control circuit generates the timing signals based on control signals fed thereto from outside by way of a number of signal lines fewer than m.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A driver IC for supplying driving currents to m groups n light-emitting diodes arranged in a row, the driver IC having n first output terminals each connected to first electrodes of m light-emitting diodes (where m 3) and having m second output terminals each connected to second electrodes m light-emitting diodes, the driver IC comprising: a data signal storage circuit for storing temporarily and sequentially at least n m data signals simultaneously, that are fed thereto; a second driver section for keeping one of the second output terminals at a predetermined potential so as to activate the light-emitting diodes connected to said one of the second output terminals; a control circuit for feeding the second driver section with designation signals for designating one of the second output terminals, and for selecting data signals corresponding to the light-emitting diodes connected to the one of the second output terminals kept at the predetermined potential from among the data signals stored in said data signal storage circuit; a first driver section for outputting the driving currents via the first output terminals in accordance with the data signals selected by the designation signals, wherein the control circuit outputs the designation signals on a basis of control signals fed thereto from outside by way of a number of signal lines fewer than m, and a number of the data signals stored temporarily and simultaneously in said data signal storage circuit is at least three times a number of said first output terminals.
2. A driver IC as claimed in claim 1 , wherein the control circuit controls the second driver section in such a way that the light-emitting diodes arranged in a row are activated sequentially as the designation signals are switched.
3. A driver IC as claimed in claim 2 , wherein the control circuit has x input signal lines (where x<m) and m output lines by way of which the designation signals are fed to the second driver section, and the data signals belonging to one of the m groups are selected from said data signal storage circuit.
4. A driver IC as claimed in claim 1 , wherein the control circuit is composed of a pulse counter circuit for counting pulses included in the control signals, which each consist of a train of pulses, and a logic circuit for combining signals output from the pulse counter circuit so as to output the designation signals to the m output lines.
5. A driver IC as claimed in claim 1 , wherein the signal lines are dedicated to the control signals.
6. A driver IC as claimed in claim 1 , wherein the signal lines are shared between the control signals and other signals.
7. A driver IC as claimed in claim 1 , wherein the first driver section includes a compensation data storage circuit for storing simultaneously compensation data for the light-emitting diodes individually, and n compensation data corresponding to one of the m groups of the light-emitting diodes are selected by way of said designation signals.
8. A driver IC for supplying driving currents to m groups n light-emitting diodes arranged in a row, the driver IC having n first output terminals each connected to first electrodes of m light-emitting diodes (where m 2) and having m second output terminals each connected to second electrodes of n light-emitting diodes, the driver IC comprising: a shift register for receiving m n data signals corresponding to the m groups n light-emitting diodes from outside; a latch circuit for storing temporarily and simultaneously at least m n data signals fed sequentially from the shift register; a data selection circuit for selecting and extracting sequentially, in batches of n data signals, the data signals stored in the latch circuit; a first driver section including a drive circuit for outputting the driving currents on a basis of the selected data signals via the first output terminals; and a second driver section for keeping one of the second output terminals at a predetermined potential so as to activate the light-emitting diodes connected to said one of the second output terminals, wherein a number of the data signals stored temporarily and simultaneously in said latch circuit is at least three times a number of said first output terminals.
9. A driver IC as claimed in claim 8 , further comprising: a control circuit for designating said one of the second output terminals that is kept at the predetermined potential by the second driver section and for feeding the data selection circuit with designation signals for designating the data signals in batches of n data signals.
10. A driver IC as claimed in claim 8 , wherein the first driver section includes a compensation data storage circuit for storing simultaneously m n compensation data corresponding to the light-emitting diodes individually, when said data selection circuit selects and extracts sequentially, in batches of n compensation data, the compensation data stored in the compensation data storage circuit, the drive circuit outputs the driving currents on a basis of the data signals and the compensation data, and a number of the compensation data stored simultaneously in said compensation data storage circuit is at least three times a number of said first output terminals.
11. An optical print head comprising a plurality of light-emitting devices, each having m groups n light-emitting elements, and a plurality of driver ICs, each corresponding to each of the light-emitting devices, for supplying driving currents to the light-emitting elements, wherein the light-emitting device has n first electrodes each connected to first electrodes of m light-emitting elements (where m 3) and m second electrodes each connected to second electrodes of m light-emitting elements, the driver IC comprises: n first output terminals connected individually to the first electrodes of the light-emitting device; m second output terminals connected individually to the second electrodes of the light-emitting device; a data signal storage circuit for storing temporarily and sequentially at least n m data signals simultaneously, that are fed thereto; a second driver section for keeping one of the second output terminals at a predetermined potential so as to activate the light-emitting elements connected to said one of the second output terminals; a control circuit for feeding the second driver section with designation signals for designating one of the second output terminals and for selecting data signals corresponding to the light-emitting elements connected to the one of the second output terminals kept at the predetermined potential from among the data signals stored in said data signal storage circuit; and a first driver section for outputting the driving currents via the first output terminals in accordance with the data signals selected by the designation signals, wherein the control circuit outputs the designation signals on a basis of control signals fed thereto by way of a number of signal lines fewer than m, and a number of the data signals stored temporarily and simultaneously in said data signal storage circuit is at least three times a number of said first output terminals.
12. An optical print head as claimed in claim 11 , wherein the light-emitting devices are laid over the driver ICs individually so that the light-emitting elements are arranged in a row.
13. An optical print head as claimed in claim 12 , wherein the light-emitting device is disposed on an upper surface of the driver IC with an electrically insulating layer sandwiched in between, and is located in a center of the driver IC having a light-emitting side thereof facing a side opposite to the electrically insulating layer, and electrical connections between the light-emitting device and the driver IC are made at longer sides of the light-emitting device.
14. An optical print head comprising a light-emitting device, having m groups n light-emitting elements, and a driver IC for supplying driving currents to the light-emitting elements of the light-emitting device, wherein the light-emitting device has n first electrodes each connected to first electrodes of m light-emitting elements (where m 2) and m second electrodes each connected to second electrodes of m light-emitting elements, the driver IC comprises: n first output terminals connected individually to the first electrodes of the light-emitting device; m second output terminals connected individually to the second electrodes of the light-emitting device; a shift register for receiving m n data signals corresponding to the m groups n light-emitting elements from outside; a latch circuit for storing temporarily and simultaneously at least m n data signals fed sequentially from the shift register; a data selection circuit for selecting and extracting sequentially, in batches of n data signals, the data signals stored in the latch circuit; a drive circuit for outputting the driving currents via the first output terminals on a basis of the extracted data signals; and a second driver section for keeping one of the second output terminals at a predetermined potential so as to activate the light-emitting elements connected to said one of the second output terminals, wherein a number of the data signals stored temporarily and simultaneously in said latch circuit is at least three times a number of said first output terminals.
15. A driver IC comprising n output terminals for driving a device, a first driver section connected to the individual output terminals, m group selection terminals, and a second driver section connected to the individual group selection terminals, wherein the first driver section comprises: a data signal storage circuit for storing simultaneously at least n m data signals that are fed thereto sequentially; a data selection circuit for selecting and extracting sequentially m times, in batches of n data signals, the data signals stored in the data signal storage circuit on a basis of control signals fed thereto from outside by way of signal lines; and a drive circuit for outputting driving currents to the output terminals on a basis of the selected data signals, and wherein the second driver section is configured to switch the m group selection terminals sequentially in synchronism with timing with which the data selection circuit selects the data signals in batches of n data signals, and a number of the data signals stored simultaneously in said data signal storage circuit is at least three times a number of said output terminals.
16. A driver IC as claimed in claim 15 , further comprising: a compensation data storage circuit for storing simultaneously m n compensation data corresponding to the n m data signals individually, wherein, when said data selection circuit selects and extracts, in batches of n compensation data, the compensation data stored in the compensation data storage circuit, the drive circuit outputs the driving currents on a basis of the data signals and the compensation data, and a number of the compensation data stored simultaneously in said compensation data storage circuit is at least three times a number of said output terminals.
17. A driver IC as claimed in claim 16 , wherein the driver IC is a driver IC for driving a light-emitting device having m groups of n light-emitting elements group by group on a time-division basis.
18. A driver IC comprising n output terminals for driving a light-emitting device having light-emitting elements, a first driver section connected to the individual output terminals, m group selection terminals, and a second driver section connected to the individual group selection terminals, further comprising: a timing control circuit for generating m division timing signals on a basis of a number of control signals fewer than m fed thereto from outside, wherein the first driver section comprises: a data signal storage circuit for storing at least n m data signals in order in which the data signals are fed thereto in order in which the light-emitting elements are arranged; a data selection circuit for selecting and extracting sequentially, in batches of n data signals, the data signals stored in the data signal storage circuit on a basis of the m division timing signals; and a drive circuit for outputting driving currents on a basis of the selected data signals, and wherein the second driver section is configured to switch the m group selection terminals sequentially in synchronism with timing with which the data selection circuit selects the data signals in batches of n data signals.
19. A driver IC as claimed in claim 18 , wherein the control signals fed to the timing control circuit are fed thereto by way of signal lines for feeding signals for controlling timing with which the data signals are stored in the data signal storage circuit.
20. A driver IC as claimed in claim 18 , wherein the control signals fed to the timing control circuit are fed thereto by way of signal lines dedicated to the control signals.
21. A driver IC as claimed in claim 18 , further comprising: a compensation data storage circuit for storing compensation data in order in which the light-emitting elements are arranged, for the n m data signals individually.
22. A driver IC as claimed in claim 21 , wherein the driver IC is a driver IC for driving a light-emitting device having m groups of n light-emitting elements group by group on a time-division basis.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
April 23, 2001
August 19, 2003
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